Bricks in Dublin

Carl de Souza, AFP/Getty Images

Irish Riot Gardai are pictured surrounded by bricks thrown by demonstrators during a protest in Dublin on the first day of Queen Elizabeth II's four-day visit to Ireland. There were two republican rallies near the Garden of Remembrance, a memorial to those who died fighting for Irish independence, where the queen was scheduled to visit later Tuesday in one of the most sensitive moments of the trip.

Irish Riot Gardai are pictured surrounded by bricks thrown by demonstrators during a protest in Dublin on the first day of Queen Elizabeth II's four-day visit to Ireland. There were two republican rallies near the Garden of Remembrance, a memorial to those who died fighting for Irish independence, where the queen was scheduled to visit later Tuesday in one of the most sensitive moments of the trip. (Carl de Souza, AFP/Getty Images)

Irish Riot Gardai are pictured surrounded by bricks thrown by demonstrators during a protest in Dublin on the first day of Queen Elizabeth II's four-day visit to Ireland. There were two republican rallies near the Garden of Remembrance, a memorial to those who died fighting for Irish independence, where the queen was scheduled to visit later Tuesday in one of the most sensitive moments of the trip.